Human cathepsin H.

W N Schwartz; A J Barrett

doi:10.1042/bj1910487

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Human cathepsin H.

W N Schwartz·A J Barrett

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Abstract

Cathepsin H was purified from human liver by a method involving autolysis and acetone fractionation, and chromatography on DEAE-cellulose, Ultrogel AcA 54, hydroxyapatite and concanavalin A-Sepharose. The procedure allowed for the simultaneous isolation of cathepsin B and cathepsin D. Cathepsin H was shown to consist of a single polypeptide chain of 28 000 mol.wt., and affinity for concanavalin A-Sepharose indicated that it was a glycoprotein. The enzyme existed in multiple isoelectric forms, the two major forms having pI values of 6.0 and 6.4; it hydrolysed azocasein (pH optimum 5.5), benzoylarginine 2-naphthylamide (Ba-Arg-NNap), leucyl 2-naphthylamide (Arg-NNap), (pH optimum 6.8). Arg-NNap and Arg-NMec, unlike Bz-Arg-NNap-, were not hydrolysed by human cathepsin B. Cathepsin H was similar to cathepsin B in being irreversibly inactivated by exposure to alkaline pH. Sensitivity to chemical inhibitors by 1 microM-leupeptin, which gave essentially complete inhibition of the other lysosomal cysteine proteinases, cathepsins B and L.

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Cathepsins Chemical Phenomena Chemistry Chromatography, DEAE-Cellulose Chromatography, Gel Humans Isoenzymes Liver Methods Substrate Specificity alpha-Macroglobulins Journal Article Research Support, Non-U.S. Gov't

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W N Schwartz, A J Barrett. 1980-11-01. Human cathepsin H.. https://doi.org/10.1042/bj1910487

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